The Transgenic Mouse Model (TMM) Laboratory at the National Cancer Institute [unreadable] Frederick provides assistance to investigators with a need to study in vivo gene function, by producing transgenic mice by pronuclear microinjection of fertilized mouse eggs. Although this service is customized to the needs of each client, the core of this effort includes purification of the DNA fragment to be microinjected and analysis of the resulting mice by Southern blot, PCR, or slot/dot blot. Consultations for the design of recombinant DNA constructs for the use in transgenic mouse studies are available. Characterization of the pattern of transgene expression at the RNA or protein level is also available. Transgenic mice are routinely produced in FVB/N and C57BL/6 backgrounds.